Add support for 'gpt-4.1' models

Close #28

Author: yethee

src/EncoderProvider.php

@@ -56,15 +56,17 @@ final class EncoderProvider implements ResetInterface
         'o1-' => 'o200k_base',
         'o3-' => 'o200k_base',
         'chatgpt-4o-' => 'o200k_base',
-        'gpt-4o-' => 'o200k_base',
         'gpt-4-' => 'cl100k_base',
+        'gpt-4.1-' => 'o200k_base',
+        'gpt-4o-' => 'o200k_base',
         'gpt-3.5-turbo-' => 'cl100k_base',
     ];
     private const MODEL_TO_ENCODING = [
         'o1' => 'o200k_base',
         'o3' => 'o200k_base',
-        'gpt-4o' => 'o200k_base',
         'gpt-4' => 'cl100k_base',
+        'gpt-4.1' => 'o200k_base',
+        'gpt-4o' => 'o200k_base',
         'gpt-3.5-turbo' => 'cl100k_base',
         'gpt-3.5' => 'cl100k_base',
         'davinci-002' => 'cl100k_base',